Shoulders are the most movable, and one of the most fragile, joints in the human body. A shoulder has a range of motion that no other joint in the body comes even close to matching. It is the shoulder's flexibility that enables the arms to be useful in a variety of activities. By moving the arm into a wide variety of positions, the shoulder multiplies the arm is usefulness. Although the shoulder is an excellent positioner for the arm, it is not a good anchor. The shoulder's flexibility makes it prone to sudden injury and chronic wear and tear. Often someone with pain in the arm, hand, or neck may have trouble moving the shoulder. Likewise, shoulder pain can affect arm and hand movement. It is natural to react to shoulder pain by not moving the shoulder, which can result in almost total loss of the ability to move the shoulder at all. Fortunately a doctor, sometimes with the aid of a physical therapist or occupational therapist, can almost always treat shoulder problems successfully, particularly if the patient follows a recommended exercise program designed to keep the shoulder in motion.
The shoulder is a complex arrangement of three bones held together by muscles, tendons, and ligaments. The clavicle, or collar bone, attaches the shoulder to the rib cage and holds the shoulder out from the trunk of the body. The clavicle connects with the large, flat, triangular scapula, or shoulder blade, at the acromion. The acromion projects from the scapula to form the top of the shoulder. The acromion in combination with the coracoid, also part of the scapula, and attaching ligaments form a socket called the glenoid fossa. The ball-like head of the humerus, or upper arm bone, is cradled in the glenoid fossa forming the glenohumeral joint, better known as the shoulder joint. The shallow ball-and-socket joint formed by the glenohumeral joint is held together by a group of tendons, known as the rotator cuff, that attach to the chest and back muscles. The bicep's tendons run out of the shoulder joint and down to the upper arm muscle. Between the acromion and the rotator cuff lies a bursa that cushions the tendon from the bone. The bursa is a small sack filled with fluid, generally the consistency of motor oil. The shoulder can move the arm around in a full circle, as well as back and forth, and up and down. Much of this motion is due to three joints in the shoulder, that serve to orient the shoulder joint itself in a given direction. One of these joints is the acromioclavicular joint. The acromioclavicular joint acts as a hinge for raising the shoulder. The scapula and humerus also play important roles in allowing full motion of the shoulder.
Common medical terms for describing shoulder movements include flexion, extension, abduction, adduction, external rotation and internal rotation. Shoulder flexion is the movement of raising the arm straight in front of the body over the head. Extension is the movement of moving the arm straight behind the body. Abduction is the movement of raising the arm out to the side over the head while keeping the arm straight. Horizontal adduction is the movement of raising the arm to shoulder height and bringing the arm out to the side, then in front of the body and out to the side again. Internal rotation is the movement of having the elbow bent and against the side of the body and moving the forearm as close to the stomach as possible. External rotation is the movement of having the elbow bent and against the side of the body and moving the forearm and hand from a position close to the stomach out to the side of the body.
The shoulder is a very vulnerable joint which typically becomes dysfunctional following neurologic disease or trauma, such as a cerebral vascular accident (stroke) or traumatic brain injury. Following a stroke or head injury, patients frequently experience paralysis on one side of their body, referred to as hemiplegia. Prior to injury, the shoulder is one joint in our body which compromises stability for mobility. Following a stroke or head injury the already unstable joint looses the muscular stability that maintains the joint integrity. As a result, the head of the humerus drops out of the glenoid fossa, resulting in what is known as a sublexed shoulder or sublexation. Furthermore, due to the cortical damage, patients are frequently left with sensory impairments or substantial pain in this region.
Occupational therapists or physical therapists are the rehabilitation professionals who patients are referred to by their physicians to treat these motor and sensory deficits. Treatment typically consists of specific neurodevelopmental techniques to facilitate normalized muscle tone, increase range or motion, decrease pain, improve coordination and eventually strength. Before normal movement can be attained the motor and sensory dysfunction, as well as the pain at the shoulder joint must be treated. Typical treatment includes techniques such as weight bearing, joint approximation and proprioceptive input through the joint to increase muscular tone in order to decrease the joint separation (sublexation) and pain. Compensatory aids, such as static arm slings are sometimes used to help with positioning of the arm as rehabilitation progresses. However, these slings have not typically been therapeutic and are fraught with controversy as they place the arm in a bent and nonfunctional position. Furthermore, they typically facilitate spasticity, which is contraindicated for the hemiplegic arm.
While occupational and physical therapies are effective ways to treat symptoms of diseases, injuries, and disabilities of various types, it typically requires an extremely long period of time before the patient reaches full o significant partial recovery. In part, this may be due to the short period of time spent in therapy, which typically may only be one hour a day. In most cases, it is only during this time period of occupational or physical therapy that the patient is properly exercising the necessary muscles in order to recuperate from the disease, injury or disability so that the patient can regain use of the affected limb or extremity. Therefore, it would be desirable in the present invention to increase the amount of time that a patient spends in therapeutic movements of the affected limb. In addition, it is desirable in the present invention to provide a patient with the ability to continue therapeutic movements throughout the day, even after leaving the supervision of the physical therapist, and more particularly, to have such therapeutic movement occur in response to normal every day activities or movements of a non-affected extremity.